1. Field of the Invention
The present invention relates to a particle detection and analysis technique and apparatus, and more particularly to a method and apparatus for detecting a distribution of particles and providing integrated moment information about the distribution.
2. Description of the Related Art
Fire safety is of considerable interest in everyday activities. It is also of great concern in the context of remote, confined spaces such as on an aircraft, spacecraft, submarine and the like. In any of these situations, the occurrence of fires can jeopardize lives and crew safety, equipment and infrastructure, flight systems, mission objectives, etc. If suitable provisions are not afforded for fire prevention and mitigation, the hazards can be considerable. Early warning fire detection is one way to mitigate such hazards.
However, designing suitable particulate sensors is challenging. Conventional state of the art fire detectors suffer from significant detection errors, and the simple strategy of increasing detection sensitivity to decrease response time leads to the problematic likelihood of false alarms. Existing standards for alarms levels are mass-based, and remain somewhat primitive in their approach and performance. Furthermore, conventional fire detection systems are, at best, poorly suited to detect reduced-gravity fire signatures such as signatures that may occur on a spacecraft.
Conventional particulate sensors for fire detection thus suffer from poor accuracy and the inability to measure specific properties or multiple properties simultaneously, and typically have a physical package that is unsuitably large, massive, power consumptive, or not mechanically robust for field deployment. In addition, accurate particulate sensors for detecting particles produced by industrial processes or environmental processes are not currently available.
Disclosed embodiments of this application address these and other issues by providing methods and apparatuses for early and accurate detection of fires or other environmental events by analyzing characteristics of radiation scattered by ensembles of particles produced by fires or by other events. Sensors described in the present application measure specific aerosol properties. For example, the sensors described herein measure light that is scattered from an ensemble of particles and provide useful integrated information about this distribution of particles. The information includes integrated moment distributions, such as, for example, total surface area, total mass, total volume, etc., or mathematical combinations of these moment distributions. Embodiments of the present application disclose a computational tool to design and optimize such sensors, as well as implementation and use of these sensors in actual practice.